The National Weather Service is predicting a system with heavy rains to move into western Montana starting Sunday and lasting most of the following week.

Senior forecaster Bob Nester provided details about the system headed this way.

“Starting Sunday we have a large area of low pressure that’s going to develop over Central Idaho and it will become a closed pressure system,” said Nester. “As always with these closed lows we can develop a widespread area of precipitation, and these systems really don’t move a whole lot over a 24 hour period so it’s going to just sit over us. As it does, there is a potential for a band of moderate to heavy rain to develop.”

Nester said the amount of rainfall will be enough to raise the river levels in western Montana.

“The amount of rainfall we’re expecting will be an inch or maybe two in the mountains,” he said. “The Clark Fork River above Missoula is forecast to react and go to near action stage at seven feet on Tuesday afternoon and they’re forecasting right now for it to peak just below minor flood stage at seven point three two feet, so it will rise, and then its forecast to go down below action stage by Thursday morning.”

Nester also referenced the moist system and how it would affect the Bitterroot River near Missoula.

“The Bitterroot River near Missoula is forecast to rise, but it won’t approach action stage,” he said. It is forecast to rise to nine point one nine feet and action stage is at 10 feet. All our rivers will rise, but it probably won’t last too long. They will peak and then go down after that.”